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71.
A possible substitution of UO2 for research purposes is the cerium dioxide (CeO2) owing to its chemical and physical properties. Neutronic properties are different and fission is absent in the case of CeO2; however, similarities were studied recently to have a possibility to compare the neutronic influence of secondary additives into the matrix. This paper deals with increasing the thermal conductivity of UO2 nuclear fuel on surrogate material (CeO2); the main focus of the research is given on the sintering behaviour of CeO2. The incorporation of highly thermally conductive material (SiC) is the investigated concept of thermal conductivity enhancement. Conventional sintering and spark plasma sintering (SPS) were applied to compare the behaviour of CeO2 and UO2 reported in the literature. High temperature thermal conductivity measurements did not confirm the positive influence of SiC additive inside the CeO2 matrix mainly due to grain boundary disruptions. Similar behaviour was also previously reported for UO2 pellets with SiC. 相似文献
72.
73.
The values of the iodine (131)I uptake determined from the measurements with a NaI scintillation counter might be significantly influenced by the thyroid position in the human neck. It is shown that the ratio of the counting rate in the energy peak of 364 keV to the counting rate in the Compton scattering band can be used for the determination of the effective depth of the thyroid. The uncertainties of the standard method are discussed basing on results of calibration measurements. The investigations of 95 patients with different thyroid diseases showed that the measured iodine spectrum was considerably different from the standard for about 20% of them, indicating possible high uncertainties of the standard measurements, which assume a fixed thyroid depth of 20 mm. 相似文献
74.
Dimitrios Vagiannis Youssif Budagaga Anselm Morell Yu Zhang Eva Novotn Adam Skarka Sarah Kammerer Jan-Heiner Küpper Ivo Hanke Tom Rozko Jakub Hofman 《International journal of molecular sciences》2021,22(21)
Tepotinib is a novel tyrosine kinase inhibitor recently approved for the treatment of non-small cell lung cancer (NSCLC). In this study, we evaluated the tepotinib’s potential to perpetrate pharmacokinetic drug interactions and modulate multidrug resistance (MDR). Accumulation studies showed that tepotinib potently inhibits ABCB1 and ABCG2 efflux transporters, which was confirmed by molecular docking. In addition, tepotinib inhibited several recombinant cytochrome P450 (CYP) isoforms with varying potency. In subsequent drug combination experiments, tepotinib synergistically reversed daunorubicin and mitoxantrone resistance in cells with ABCB1 and ABCG2 overexpression, respectively. Remarkably, MDR-modulatory properties were confirmed in ex vivo explants derived from NSCLC patients. Furthermore, we demonstrated that anticancer effect of tepotinib is not influenced by the presence of ABC transporters associated with MDR, although monolayer transport assays designated it as ABCB1 substrate. Finally, tested drug was observed to have negligible effect on the expression of clinically relevant drug efflux transporters and CYP enzymes. In conclusion, our findings provide complex overview on the tepotinib’s drug interaction profile and suggest a promising novel therapeutic strategy for future clinical investigations. 相似文献
75.
LDPE/PA6 binary blends and LDPE/PA6/compatibilizer ternary blends were prepared in a Brabender extruder, equipped with a prototype static mixer. Compatibility of the components was estimated by rheological properties (viscosity and a melt flow index), and observations of the structure were made with the help of scanning electron microscopy and tensile strength. It was found that the blends' structure and properties are dependent on the recipe content of the polymer blends and the conditions of their manufacturing. Uniformity of the blends of the thermodynamically immiscible polymers was improved by using a prototype static mixer giving mechanical compatibilization and a compatibilizer giving chemical compatibilization. LDPE grafted with a maleic anhydride (LDPE-g-MAH) was used as a compatibilizer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 719–727, 1998 相似文献
76.
Jakub W. Strawa Katarzyna Jakimiuk Micha Tomczyk 《International journal of molecular sciences》2021,22(24)
The use of plants as traditional medicines is common and has prevailed in many different cultures over time. Polymethoxyflavones (PMFs) are natural polyphenols from the group of flavonoids. Zapotin, a member of the PMFs, is found mainly in citrus plants and is almost exclusively limited to their peels. The chemical structure of zapotin has been questioned from the very beginning, since the structure of flavonoids with a single oxygen atom in the C2′ position is extremely rare in the plant kingdom. To clarify this, the structural determination and bio-inspired synthesis of zapotin are discussed in detail in this review. Due to the broad biological potential of PMFs, the complication in the isolation process and characterization of PMFs, as well as their purification, have been estimated by adapting various chromatographic methods. According to available data from the literature, zapotin may be a promising curative agent with extensive biological activities, especially as a chemopreventive factor. Apart from that, zapotin acts as an antidepressant-like, anticancer, antifungal, and antioxidant agent. Finally, accessible studies about zapotin metabolism (absorption, distribution, metabolism, excretion, and toxicity) underline its potential in use as a therapeutic substance. 相似文献
77.
G protein-coupled receptor 55 (GPR55) is a recently deorphanized lipid- and peptide-sensing receptor. Its lipidic endogenous agonists belong to lysoglycerophospholipids, with lysophosphatidylinositol (LPI) being the most studied. Peptide agonists derive from fragmentation of pituitary adenylate cyclase-activating polypeptide (PACAP). Although GPR55 and its ligands were implicated in several physiological and pathological conditions, their biological function remains unclear. Thus, the aim of the study was to conduct a large-scale re-analysis of publicly available gene expression datasets to identify physiological and pathological conditions affecting the expression of GPR55 and the production of its ligands. The study revealed that regulation of GPR55 occurs predominantly in the context of immune activation pointing towards the role of the receptor in response to pathogens and in immune cell lineage determination. Additionally, it was revealed that there is almost no overlap between the experimental conditions affecting the expression of GPR55 and those modulating agonist production. The capacity to synthesize LPI was enhanced in various types of tumors, indicating that cancer cells can hijack the motility-related activity of GPR55 to increase aggressiveness. Conditions favoring accumulation of PACAP-derived peptides were different than those for LPI and were mainly related to differentiation. This indicates a different function of the two agonist classes and possibly the existence of a signaling bias. 相似文献
78.
Association studies on the porcine RETN, UCP1, UCP3 and ADRB3 genes polymorphism with fatness traits
Jakub Cieslak Joanna Nowacka-WoszukMagdalena Bartz Honorata Fijak-NowakMaria Grzes Maciej SzydlowskiMarek Switonski 《Meat science》2009
Searching for effects of candidate gene polymorphisms on fatness traits is an important goal for pig industry. In this study we evaluated polymorphism of four porcine genes involved in energy metabolism (RETN, UCP1, UCP3 and ADRB3). Moreover, their association with fat deposition traits was analyzed in two breeds (Polish Landrace, Polish Large White) and a Polish synthetic line (L990). Altogether, five SNPs were identified, including two novel ones in the 5′-flanking region of the RETN gene and a novel missense substitution in the UCP3. Distribution of these polymorphisms in the studied five breeds and the synthetic line was not uniform. Two of the analyzed SNPs: g.−178G > A in the RETN and g.946C > T in the UCP3 gene revealed a significant association with abdominal fat weight or backfat thickness. Such associations were not observed for the UCP1 or ADRB3 gene polymorphisms. Our study showed that polymorphisms of the UCP3 and RETN genes are potentially associated with porcine fatness traits. 相似文献
79.
Martina Polaskova Roman Cermak Tomas Sedlacek Jakub Kalus Martin Obadal Petr Saha 《Polymer Composites》2010,31(8):1427-1433
Extrusion of immiscible polymers under special conditions can lead to creation of microfibrillar‐phase morphology, ensuring significant increase of mechanical properties of polymer profiles. Polyethylene/polypropylene blend extrudates with microfibrillar‐phase morphology (polypropylene microfibrils reinforcing polyethylene matrix phase) were prepared through continuous extrusion with semihyperbolic‐converging die enabling elongation and orientation of microfibrils in flow direction. Structure of extruded profiles was examined using electron microscopy and wide‐angle X‐ray scattering. Tensile tests proved that extrudates with microfibrillar‐phase morphology show significantly higher mechanical properties than the conventional extrudates. The presented concept offers possibility of replacing the existing expensive multi‐component medical devices with fully polymeric tools. POLYM. COMPOS., 31:1427–1433, 2010. © 2009 Society of Plastics Engineers 相似文献
80.
Miloš Janeček Jakub Čížek Jenő Gubicza Jitka Vrátná 《Journal of Materials Science》2012,47(22):7860-7869
Commercial MgAlZn alloy AZ31 was processed by hot extrusion and equal channel angular pressing (ECAP) known as EX-ECAP. Microstructure and defect structure evolution with strain due to ECAP were investigated by TEM, positron annihilation spectroscopy (PAS), and X-ray diffraction. Significant grain refinement was obtained by EX-ECAP. In the extruded condition relatively low density of dislocations was determined by PAS. Sharp increase of dislocation density occurred during the first two passes of ECAP, followed by the saturation and even a decline manifesting the dynamic recovery at higher strains. XRD line profile analysis confirmed the results of PAS with slightly higher values of dislocation densities in individual conditions. Detailed analysis of contrast factors allows to determine the type of dislocations and to draw conclusions about slip activation and its variations with strain. The influence of microstructure evolution on mechanical properties is discussed. 相似文献